Brad is anal retentive. No, he's not fixated on order, nor does he insist on eating the same thing every night in a particular way, like say chicken fingers with cheese and fruit (hat tip to Kia). Brad is not anal in the freudian sense.
Brad is literally holding in his shit.
This is a new development. He had a few poop accidents in the wake of his potty training, and now he's freaked out. We've got issues.